Ok this is hard one to explain! I just want to know if it is normal. Ok when you first turn the key on you here the pump run its one steady sound then when you start the truck it gets a little bit diff in sound but when i am driving i dont here it do to the stacks on the tuck but when i come to a red light stop sign or sit and ideal i hear the pump make its normal sound but then it changes a little in the sound then right back to the normal sound and it keeps doing that its like 2 tones of sound back and forth real fast. The truck runs great so far and i only have had this in for a few months and i dont remember it doing this but not sure. thanks all mine is on a 04.5 ram cummins.

 

What does your fuel pressure guage say?

 

May be air in the system

 

says 0 its still in the box have not hooked it up yet. My bad. But the truck runs great even on the hot setting.why?

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if its air i should be able to open the the one filter and just fuel comes out.

 

Ive heard about every pump change its tone when it wants to I wouldnt worry about it

 

Ya i have not heard anyone elses yet. it almost sounds like it builds up and then lets go maybe its the fuel returning to the tank.

 

I dont think this is anything major to worry about either...but I would get the FP guage hooked up. Its a great troubleshooting tool.

 

Ya i plain on doing that this weekend. But everyone is telling me the common rail i should get the rail presure gauge instead. what kind of numbers should the fuel presure gauge read too.

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ya and these pumps sure are not quiet wow.

 

The pressure gauge is as said a great tool but I'll tell you what I know about the FASS products.

1. the tone will change based on the quality and age of the filters.
2. the tone will change if there is air locked in the pump.
3. the tone will change if your tank is very low or the stock dip tube still has the screen on the end of it and it is getting plugged.
4. the tone will change if you have a hole on the section side

Nothing to be really worried about though.

 

The Noisy Pumps are miss aligned Gears in the Pump